The present invention provides methods for detecting pregnancy in a woman. In particular, the methods comprise screening biological samples for biological markers associated with pregnancy. One aspect of the invention is related to the discovery that using a combination of two capture antibodies that specifically bind different epitopes of ITA in one assay improves the sensitivity of the assay for the biological markers.
In one embodiment of the invention, a method for detecting pregnancy in a woman comprises the step of: contacting a biological sample of the woman with antibodies that bind invasive trophoblast antigen (ITA), in a chemiluminescent assay, wherein the assay comprises at least two antibodies that specifically bind different epitopes of the ITA, wherein a label coupled to at least one of the two antibodies produces a detectable signal, and wherein the presence of a detectable signal indicates pregnancy in the woman.
In another embodiment of the invention, a method for detecting pregnancy in a woman comprises contacting a biological sample of the woman with antibodies that bind ITA in an assay, wherein the assay comprises at least two antibodies that specifically bind different epitopes of ITA, wherein a label coupled to at least one of the two antibodies produces a detectable signal.
In another embodiment of the invention, a method for detecting pregnancy in a woman comprises contacting a biological sample of the woman with antibodies that bind at least one pregnancy marker in one assay, wherein the assay comprises at least two capture antibodies that specifically bind different epitopes of the marker, and at least one detection antibody that specifically binds an epitope of the marker different from the epitopes bound by the capture antibodies, and wherein a label coupled to the detection antibody produces a detectable signal. In certain embodiments, the pregnancy markers comprise ITA, human chorionic gonadotropin (hCG), or fragments thereof. In other embodiments of the invention, the pregnancy markers comprise a combination of ITA and hCG, or fragments thereof.
In another embodiment of the invention, a method for detecting pregnancy in a woman comprises contacting a biological sample of the woman with antibodies that bind ITA in one assay, wherein the assay comprises at least two capture antibodies that specifically bind different epitopes of ITA, and at least one detection antibody that binds an epitope of ITA different from the epitopes bound by the capture antibodies, and wherein a label coupled to the detection antibody produces a detectable signal.
The foregoing methods can also be practiced by contacting the biological sample with antibodies that bind at least one additional pregnancy marker, such as hCG, or a fragment thereof.
In yet another embodiment of the invention, a method for detecting pregnancy in a woman comprises contacting a biological sample of the woman with antibodies that bind ITA and hCG, in one assay, wherein the assay comprises at least two capture antibodies that specifically bind different epitopes of the ITA and hCG, and at least one detection antibody that binds an epitope of the ITA and hCG different from the epitopes bound by the capture antibodies, and wherein a label coupled to the detection antibody produces a detectable signal.
In certain embodiments of the invention, the capture and detection antibodies of the foregoing methods are monoclonal antibodies. Examples of capture antibodies include monoclonal antibodies designated B152, clone 827, and clone 820. Examples of detection antibodies include the monoclonal antibody designated B207.
In another embodiment of the invention, a method for detecting pregnancy in a woman comprises a) contacting a biological sample of the woman with a capture antibody designated B152; and b) contacting the biological sample with a detection antibody designated B207, wherein the capture and detection antibodies recognize and bind different epitopes of ITA, and wherein the the detection antibody is coupled to a label that produces a detectable chemiluminescent signal.
In yet another embodiment of the invention, a method for detecting pregnancy in a woman comprises contacting a biological sample of the woman with antibodies that bind ITA and hCG, in one assay, wherein the assay comprises at least two capture antibodies, designated B152 and clone 827, that specifically bind different epitopes of the ITA and hCG, and at least one detection antibody, designated B207, that binds an epitope of the ITA and hCG different from the epitopes bound by the capture antibodies, and wherein the detection antibody is coupled to a label that produces a detectable signal.
The biological samples used in the methods of the invention include liquid or tissue samples. Liquid samples include urine, whole blood, serum, plasma, or amniotic fluid. Tissue samples include vaginal tissue or placental tissue.
In some embodiments of the invention, the detectable signals may be obtained by measuring the luminescence of an acridinium ester.
The foregoing methods can be practiced within about seven days after ovulation or in vitro fertilization. In some embodiments, the methods are practiced within about five days of ovulation, or within about four days of in vitro fertilization.
The assays of the foregoing methods may be automated.
Any feature or combination of features described herein are included within the scope of the present invention provided that the features included in any such combination are not mutually inconsistent as will be apparent from the context, this specification, and the knowledge of one of ordinary skill in the art.
Additional advantages and aspects of the present invention are apparent in the following detailed description and claims.